I wonder if Till's talking about his anxiety/depression, especially with the ending. Like it's something that's always there that he can't control (he's "sweating" even when it's cold). He can't tell if he's ashamed of it, because other people tell him it's not sweat, it's TEARS and maybe that's hard for him to come to terms with. "Sweating" is a barrier in the narrator's life. Preventing him from having relationships (I wonder if this means friendship too) as it causes a physical and emotional barrier. Hard to really know what it's truly about but I have a feeling it's about his mental health issues with depression and anxiety.
